Final Report - Team I

THE JAR CAROUSEL

FINAL REPORT

ME 340 SECTION 4

TEAM I

April 29, 2011

DAN AGLIONE MATT STEINDORF

QI ZHANG

Team I Final Report i | P a g e 4/29/2011

EXECUTIVE SUMMARY

This design report focuses on the design of a kitchen product that automatically opens and closes jars of various sizes. The jar opener is powered by a rechargeable battery pack, requiring no human power to operate. This product lends assistance to those who struggle with jar usage due to physical limitations, while illustrating a durable, cost efficient product that can fit any home. Of course, safety and ease of use are of utmost importance.

The report outlines the details of a comprehensive design process used to incorporate features deemed desirable by potential users. An extensive customer need assessment was completed, as well as product benchmarking to accurately access the product’s market. With these needs, complimentary design specifications were yielded, providing the basis for many concept variants. A final concept was selected after methodically utilizing weighted criteria. This design contains a cone infused under a rotating carousel that supplies torque to lids of varying diameters. The bottom of the jar is held in place via a diamond clamp system that pivots around four pins to allow for adjustability. Two electric motors supply power to both the cone and clamp by means of two gearing systems. Engaging the top and bottom mechanisms is done by using two switches that can spin each motor in both directions. When assembled, all of the components work together to deliver a fast and easy approach to jar opening.

The final product, called the Jar Carousel, will cost approximately $26 to manufacture and assemble. With current market estimates, the product is anticipated to sell 100,000 units annually for a duration of 4 years. If sold at a unit price of $50, the product will yield a profit of $1.3 million over its lifetime. The Jar Carousel can become both a wise investment and a companion of consumer countertops.

Team I Final Report ii | P a g e 4/29/2011

TABLE OF CONTENTS

Page

Executive Summary……………………………………………………………………......……………………….. …i

1. Introduction

Problem Statement……………………………………………….……………………………..…. ..1

Background……………………………………………………………… ………………………...…...1

1.1 Task Description……………………………………………………………………….….…….2

Project Planning………………………………………..…………………….................. .…….2

2. Customer Needs Assessment

Gathering Customer Input………………………………………………………...…… ..….2

Weighing Customer Needs…………………………………………………………….....….3

Developing Design Specifications…………………………...………………….…. .…3-4

3. Concept Generation

External Search………………………………………………………………………….……... ..4

Problem Decomposition……………………………………………………………….….. ...5

Ideation Methods…………………………………………………………………….…….. ..….5

Description of Design Concepts……………………………………..……...…..…… .......6

4. Concept Selection

Concept Screening……………………………………………………………..…….....……6-7

Concept Scoring………………………………………………………...…........ ..................7-8

5. System Level Design…………………………………………………………...…...………………...8-10

6 Detailed Design

Proposal Modifications………………………………………………………….…..... ……11

Component Selection…………………………………………………..................……11-12

Material Selection……………………………………………………….....................…12-13

CAD Models and Drawings ………………………………………………………..….13-15

Fabrication Process……………………………………………………………….…..…15-16

Bill of Materials……………………………………………………….…………..….… .……..17

Economic Analysis……………………………………………………………..……...…18-19

Performance Calculations……………………………………………………..…..… .19-20

Testing Procedure…………………………………………………………………….….20-21

7. Alpha Prototype…………………………………………………………………………………...… .21-24

8. Beta Prototype……………………………………………………………………….…….…………..24-25

9. Test Results and Discussion ………………………………………………….….… ……………26-27

10. Conclusions and Recommendations………………………………………….……… ..….….27-28

11. References……………………………………………………………………………….…………..…… .…28

Appendix A - Project Management……………………………………………………………….…....…28-29

Appendix B - Customer Data………………………………………………………………………… ….....……30

Appendix C - CAD Models and Detailed Drawings……………………………………….…... ...…31-35

Appendix D - Calculations………………………………………………………………………………...….36-40

Appendix E - Prototype Fabrication……………………………………………………….……… ….…41-43

Appendix F - Concept Sketches…………………………………………………………………………….44-49

Team I Final Report 1 | P a g e 4/29/2011

1. INTRODUCTION

1.1 Problem Statement

Often times, separating a lid from a jar can be an extremely frustrating task. Jar opening should be a simple and trivial process, but needs for tremendous effort and a perfect gripping technique can hinder its simplicity. These struggles may be caused by vacuum sealing, dirty threads, or slippery lid design. In a market where can openers, bottle openers, and pull-back tabs exist, a technology is desperately needed to assist in the jar opening process as well.

Senior citizens, users with physical conditions, or amputees struggle most of all. Currently, this population is forced to implement all sorts of methods to remove lids. Some use towels to avoid severe gripping pains. Others try schemes like banging the lid or soaking the jar with hot water. Worst of all, a large number of people cannot open tough jars independently and are forced to wait for assistance.

A jar opening product would be the perfect answer to these problems. This device would be able to automatically open and close the lids of jars without requiring human power whatsoever. Users would be able to rid their lives of all opening antics and use any jar, worry free. Because jar technology will not be changing in the near future, a jar opening tool is the only viable solution.

1.2 Background

The volume of food storage has greatly escalated over the past 50 years. Great strides have been taken to preserve items fresher and for longer periods of time. Today, jars continue to be a staple in household food storage. Although they are versatile and elementary in nature, a basic twist can be surprisingly troublesome.

For a large portion of the population, certain physical limitations create difficulties with jar usage. Arthritis, for example, is a prevalent condition that damages the joints in the body. In common types such as osteoarthritis and rheumatoid arthritis, hand capabilities can be severely reduced. According to the Centers for Disease Control and Prevention, an estimated 22% of Americans report having doctor diagnosed arthritis. Approximately 29 million adults suffer from either osteoarthritis or rheumatoid arthritis [1].

Senior citizens as well as amputees can also struggle with jar opening. The design of a jar requires equal and opposites torque on both the jar and lid. For those without two functioning hands, applying this torque is challenging. Other times, jars may need more force than the user can provide. Especially with gunked up threads and slippery lids, the ability to supply the required action can be a prohibiting nightmare.


1.3 Task Description

The task of this project is to develop a product that can automatically open and close jars of various sizes. The final concept utilizes a rechargeable battery from a cordless drill to provide 100% of the power. No assembly will be needed by the customer. The design addresses the concerns of users in an elegant, safe, and ergonomic package.

1.4 Project Planning

This report documents an elaborate design process that will be carefully followed to develop a viable solution to the task description. To begin the research, customer needs are assessed to fully understand what ideas need to be incorporated into the design. This involves customer feedback regarding benchmark items. Secondly, the needs are translated into appropriate product specifications. The next step involves concept generation based on the specifications. A concept generation table is used to create many concept permutations. The most promising designs then undergo comparison in screening and scoring matrices with appropriate criteria weights. The results of the scoring accurately indicate the best design.

The final design will undergo significant analysis to assess its economic and technical viability. Prototypes will be fabricated to help test the mechanisms as well as stimulate iterations and refinement. At the completion of the design process, the product will be ready to manufacture for the awaiting market.

A proposed timetable of the project schedule can be seen in Appendix A, Figure 2.1.

2. CUSTOMER NEEDS ASSESSMENT

2.1 Gathering Customer Input

Customer inputs were collected through customer reviews of Black Decker Lids Off Jar Opener and One Touch Jar Opener, which are the existing benchmark products on market [2, 3]. These benchmark items provided feedback from actual users. These reviews are of utmost importance because the needs come straight from the product market. Customer statements were then translated into interpreted needs as criteria in designing the jar opener. Along with the customer inputs, the team also added basic criteria such as safety and efficiency. This table can be viewed in Appendix B, Table 2.1on page 29.


Aesthetics Ergonomics Ease of Storage Affordable One Size Fits All Durability Energy Efficient Long Lifetime Ease of Operation Quiet Safety Projected Torque Total Weight

Aesthetics 1 0.2 0.33 0.2 0.25 0.33 3 0.5 0.2 2 0.25 0.33 8.59 0.0379

Ergonomics 5 1 2 3 2 4 5 4 1 5 2 3 37 0.1633

Ease of Storage 3 0.5 1 1 0.5 0.5 2 1 0.2 2 0.33 0.5 12.53 0.0553

Affordable 5 0.33 1 1 2 3 4 2 0.33 2 1 1 22.66 0.1000

One Size Fits All 4 0.5 2 0.5 1 2 2 1 0.25 2 1 0.5 16.75 0.0739

Durability 3 0.25 2 0.33 0.5 1 3 2 0.33 4 0.5 1 17.91 0.0791

Energy Efficient 0.33 0.2 0.5 0.25 0.5 0.33 1 0.33 0.2 1 0.25 0.33 5.22 0.0230

Long Lifetime 2 0.25 1 0.5 1 0.5 3 1 0.25 2 0.33 0.33 12.16 0.0537

Ease of Operation 5 1 5 3 4 3 5 4 1 5 3 3 42 0.1854

Quiet 0.5 0.2 0.5 0.5 0.5 0.25 1 0.5 0.2 1 0.25 0.33 5.73 0.0253

Safety 4 0.5 3 1 1 2 4 3 0.33 4 1 2 25.83 0.1140

Projected Torque 3 0.33 2 1 2 1 3 3 0.33 3 0.5 1 20.16 0.0890

Total 226.54 1.0000

2.2 Weighing Customer Needs

The weighing of criteria is an essential step in developing a concept. This gives a quantitative representation of how each criterion relates to one another. Not all criteria are equally important, thus they should not have the same impact during the scoring process.

In order to effectively weigh each criterion as it relates to the product, an Analytical Hierarchy Process (AHP) Pairwise Comparison Chart was developed (See Table 2.1 below). Here, the relative importance of the twelve criteria were compared to one another, using a rating system from 1-5. A score of 1 indicated that the two requirements shared equal importance. A higher number specified more of an importance in relation to the other criterion. This process was completed until all comparisons were covered. The summation of the scores then provided a total which signified the weighted value of the criteria. These values translated into the weights found in the scoring matrix for final concept selection [4].

Scale of Relative Importance

1=equal 2=moderately important 3=strong importance 4=very strong 5=extreme importance

2.3 Developing Design Specifications

It is extremely important to design a product that meets customer needs. This is done by adapting customer feedback into engineering specifications that will be used in the product design. A tool to accomplish this is quality function deployment (QFD) [4]. This matrix lists customer needs on the y axis and engineering specifications on the x axis.

Table 2.1: AHP Diagram


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Customer Need

Aesthetically Pleasing X X X X

Ergonomic X X X X

Compact Storage Space X

Affordable X X X

Fits various jar heights X

Fits various jar widths X

Speedy Operating Time X X X

Require less human power X X X X

Supplies Enough Force X X X

Safe Opening Action X X

Sturdy Design X X

Inside the matrix are X marks where a particular need corresponds to a design feature. Many needs can be addressed by one specification and vice versa.

Figure 2.2: Quality Function Decomposition

3. CONCEPT GENERATION

3.1 External Search

While investigating possible solutions to open and close jars, several products were found that are already have some of the desired functionality. Two of the most prominent products found were the Black & Decker Lids-Off Jar Opener and the One Touch Jar Opener [2, 3]. These two products both open jars under their own power, but fail to close any jars. The mechanisms that drive both of these products only support torqueing the lids off in a counterclockwise motion and could not mechanically grip the jar when running in reverse.


3.2 Problem Decomposition

The product must be able to fulfill the customer needs and, by doing so, will be the only product in the market to open jars with lid diameters up to 3.5 inches and also be able to close them as well.

The jar opener is decomposed into a black box to simplify the jar opening/closing process [4]. Energy from the battery source, signal from the operator using the buttons, and setting up the jar placement are all that are required as inputs. After the product performs its task, out comes an opened or closed jar without any mess or hassle.

Figure 3.1: Overall Black Box of Design

3.3 Ideation Methods

Concepts were generated using brainstorming, benchmarking, and a combination table process [4]. Initially, each team member researched related items and sketched some original ideas. It was established that a successful jar product would have a few fundamental principles. These principles included how the bottom of the jar would be held, how the lid would twist off, any mechanical processes involved, and finally which parts were moving. The combination table lists characteristics for each of the four categories. These characteristics are shown in Table 3.1 on page 6.

Input Output

Energy Jar Opened /Closed

Signal Signal (?)

Setup No Mess

Gears

Electric Motors

Switches


Table 3.1: Design Concept Classifications for Concept Combination

Lid Fastening Mechanism

Container Fastening Mechanism

Mechanical Process Used

Which part of Jar is Powered

Scissoring Wedge

Cone Central Axis Rotation Top Jar

Clamps Scissoring Wedge Tangential Rotation Bottom Jar

Strap/Band Rounded Clamps Linear Opposition Top Structure of Product

Tire Pressure on Lid

Tire Pressure on Jar Walls

Bottom Structure of Product

Handcuff Style Clamps

Diamond Wedge Both Top and Bottom Powered

3.4 Description of Design Concepts

Several concepts were created by selecting different elements from each column of the concept combination table [4]. These concepts are detailed in Appendix F, Figures 3.2-3.7. Each concept utilized a different permutation of the four columns in new and creative ways. By choosing these from a list, it was more difficult to have a bias while generating concepts.

4. CONCEPT SELECTION

4.1 Concept Screening

A concept screening matrix was used to determine the most viable concepts out of the six that were chosen from the combination table. The Strap Bottom/Cone Top, Adjustable Diamond/Cone Top, and the Belt Driven Top/Strap Bottom designs were identified as these three designs. The criteria used to judge each concept came from the customer needs assessment. The customer needs were analyzed based on translating reviews into interpreted needs and desired specifications. This analysis can be found in Appendix B, Table 2.1. The Concept Screening Matrix can be found in Table 4.1 on the following page.


4.2 Concept Scoring

The Strap Bottom/Cone Top, Adjustable Diamond/Cone Top, and the Belt Driven Top/Strap Bottom designs were again ranked using the concept scoring matrix. For this matrix, the relative weights for the customer needs were calculated using the results from the Analytical Hierarchy Process found on page 3, Table 2.1. The scoring results can be found in Table 4.2 on page 31. It was determined that Adjustable Diamond/Cone Top performed the best in the concept screening matrix and was selected for the system level design. This selection seemed both logical and appropriate since it best fulfilled the larger weighted criteria.

Scissor

Bottom/Tires Top

Strap Bottom/

Cone top

Scissor

Bottom/Straight

Clamp top

Scissors bottom,

handcuffs top

Adjustable

Diamond

bottom/ Cone

top

Belt

Driven Top

strap

bottom

aesthetics 1 1 0 0 1 1

ergonomics -1 -1 0 0 -1 -1

easy for storage 0 -1 0 0 1 1

affordable -1 0 0 1 -1 -1

one size fit all 1 0 0 0 0 1

durability 0 1 0 0 1 -1

energy efficient -1 0 0 0 0 -1

long lifetime 0 0 0 0 0 0

easy to operate 1 1 0 0 1 1

quiet 0 0 0 0 0 0

safety 0 1 0 0 1 1

projected torque 1 0 0 0 0 1

Sum + 4 4 0 1 5 6

Sum 0 5 6 12 11 5 2

Sum - 3 2 0 0 2 4

Net Totals: 1 2 0 1 3 2

Rank 4 2 6 4 1 2

Continue? No Yes No No Yes Yes

Table 4.1: Concept Screening Matrix


Table 4.2: Concept Scoring Matrix

5. SYSTEM LEVEL DESIGN

The final design encompasses the adjustable diamond bottom/cone top iterations. This concept utilizes three separate actions to open the jar. First the user has to activate the gold section (cone) and raise it out of the way. The user then inserts the jar into the center of the base, in between the four walls of the diamond clamp. The four walls are held together by pins which are mounted in gliding paths on the base plate of the device. The user then lowers the cone and secures the jar by activating the rack and pinion on the base. The rack and pinion assembly either pulls or pushes one of the diamond pins toward or away from the jar center. A pushing motion enlarges the area inside the diamond, whereas a pulling action squeezes the rigid diamond walls together.

After the base of the jar is secure, there is a toggle switch where the user can select either to open or close the jar lid. This action rotates the blue section of the jar opener around a center axis beneath the gray base plate, causing the cone to rotate as well. The weight of the top mount provides the necessary contact pressure to the lid. After the

Relative

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Belt

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Selection

Criteria Rating

Weighted

Score Rating

Weighted

Score Rating

Weighte

d Score

aesthetics 0.0379 3 0.1137 3 0.1137 3 0.1137

ergonomics 0.1633 2 0.0758 3 0.1137 1 0.0379

ease of storage 0.0553 3 0.1137 3 0.1137 3 0.1137

affordable 0.1 3 0.1137 2 0.0758 2 0.0758

one size fit all 0.0739 3 0.1137 3 0.1137 4 0.1516

durability 0.0791 3 0.1137 4 0.1516 2 0.0758

energy efficient 0.023 3 0.1137 3 0.1137 2 0.0758

long lifetime 0.0537 3 0.1137 3 0.1137 3 0.1137

ease of operate 0.1854 2 0.0758 4 0.1516 4 0.1516

quiet 0.0253 3 0.1137 3 0.1137 3 0.1137

safety 0.114 3 0.1137 4 0.1516 2 0.0758

projected torque 0.089 3 0.1137 3 0.1137 4 0.1516

Totals: 1.2886 1.4402 1.2507

Continue? No Develop No


required number of revolutions, the lid has either been removed or securely fastened to the jar. The user lifts up the gold cone section and removes the jar and lid. This system allows the user to easily operate the entire process with as little effort as possible. As long as the user is able to lift up the jar and place it in the center, they are able to perform the necessary motions to use this system.

The system will be constructed from injection molded plastic, allowing for an adequate strength to cost ratio. The materials for the design prototype will be primarily stock materials, with the needed gears and motors being supplied 'as is'.

Preliminary CAD sketches of the design are shown below (Fig 5.1-5.5).

Figure 5.1: Jar Opener Isometric

Figure 5.2: Diamond Wedge Position 1 Figure 5.3: Diamond Wedge Position 2


Figure 5.4: Rack and Pinion

Figure 5.5: Section Cut


6. DETAILED DESIGN

6.1 Proposal Modifications

The Jar Carousel detailed design has undergone some revisions since the system-level design stage. These changes are the result of performance calculations, alpha prototype fabrication, and testing procedures.

The first major change was made with the cone top support. It now rotates via a drive gear positioned on the perimeter of a large carousel gear. The system- level design initially proposed a center of axis rotation. However, this method was not feasible because the diamond clamp assembly could not be supported if rotating spokes were moving underneath. The motor and threaded rod system needed to be directly below the clamps in the same position as a potential center of axis rod. The drive gear approach allows the clamp to operate without any interference.

Secondly, an additional support rod was added to the carousel assembly whereas it originally only contained two support rods. This revision was implemented to enhance the structural integrity of the cone rotation. Three supports also allow the cone top to rotate and rest on the rods when loading and unloading a jar, a feature necessary for one-hand use.

Finally, the diamond clamp assembly used to fix the bottom of the jar was modified. Initially, an electric motor would translate the drive pin using a rack and pinion system. The new design calls for a threaded rod and tapped block assembly to transform rotational motion to linear displacement. A rack and pinion cannot maintain its position without being powered. As soon as the motor is turned off, the drive pin would be free to move, sacrificing the clamps’ contact pressure on the jar. The threaded rod and block system will lock in place with or without the motor being used. This is an essential quality to have since the user should not have to press the clamp switch for the entire duration of the jar opening process.

6.2 Component Selection

The Jar Carousel consists of an array of components that all work together to deliver a durable and effective product. The foundation of the product is comprised of the base and side housings. Inside this foundation consists of two electric motors, a worm, three spur gears, and a threaded rod with drive pin coupling. The spur gears have 10 or 20 teeth to deliver the appropriate torque and speed ratios (See 6.8 Performance Calculations). A 3/8-24 threaded rod was used to yield a favorable angular to linear speed ratio due to its pitch measurement. The drive pin passes through the housing and moves to the diamond clamp system above.


The diamond clamp system contains four clamps and pins that act as hinges to secure the bottom of the jar. The pins follow linear tracks cut into the housing to permit smooth motion. Around the diamond clamp is a large carousel gear rotating on a turntable. The carousel gear is spun with a drive gear that links to the gear assembly inside the housing. Three support rods are press fitted into the carousel gear. These serve to guide a cone top piece up and down to accommodate various jar heights. A cone shaped cutout is present under the top piece and lined with rubber to apply torque to the jar lid. The cone design accommodates various jar diameters.

The Jar Carousel is powered by an 18 V rechargeable battery pack. This is conveniently mounted to the side of the housing to allow for easy attachment. Two toggle switches are positioned on the front side of the housing. One switch is wired to the carousel gear motor, while the other is wired to the threaded rod motor. Both switches have three positions: up, neutral, down. Clicking the switches upwards will rotate the electric motors in a clockwise fashion. Pressing down on the switches rotates the motors in the opposite direction. This design makes it possible for the carousel to open and close the jar lid, and the clamp to tighten and loosen its contact pressure on the jar bottom.

6.3 Material Selection

ABS There were several factors to consider in material selection of components. ABS

was chosen as the material for the housing, support rods, cone top piece, diamond clamps, pins, and threaded rod assembly. ABS (acrylonitrile butadiene styrene) is a cost effective acetyl plastic that is a popular choice for its toughness and impact resistance [5]. Making several components out of the same material will minimize costs and the material can be purchased from a single supplier. Molds can be made to form the ABS plastic into the

Figure 6.1: Diamond Clamp/Turntable

Figure 6.2: Gears/Rods/Cone Top


specific components. This means a single company can tailor the design of the molds to match the characteristics of ABS plastic in the injection molding process. Rubber

The diamond clamp and cone top deliver torque to the jar in the form of static frictional forces. ABS cannot transfer large frictional contact forces to the jar because its coefficient of friction with the jar is quite low. The jar would spin even when clamped in position. To accommodate this, rubber was chosen to line the inner clamp walls and the inside of the cone top. Rubber has the necessary coefficient of friction properties with the jar to ensure the torque is transferred without slippage. Delrin

All of the gears in the product will be made from Delrin (scientifically called polyoxymethylene (POM)). This material was developed by DuPont and is characterized by its high strength, hardness, and rigidity [6]. Its tremendous stiffness and low friction coefficients make Delrin a great material for gears where both properties are important. Out of the plastics, Delrin is the best choice to deliver durability and strength. Metal gears are not used because of the unnecessary weight burden, especially for the large carousel gear. That gear alone would add a few pounds to the jar opener, but would not provide any significant advantage over Delrin.

6.4 CAD Models and Drawings

SolidWorks was extensively used to model the Jar Carousel. The model contains every component that will be used for mass production. The component interfaces, tolerances, and dimensions are accurately included.

Below are some pictures and dimensions of the Jar Carousel assembly to display basic product characteristics and functionality. Additional detailed pictures of subassemblies and components can be found in Appendix C on pages 31-32.

Figure 6.3: Jar Carousel


These transparent views show the inside workings of the product. The threaded rod assembly is positioned directly in the center of the housing since the diamond clamps are centered above. The worm connects with a shaft near the edge to engage the drive gear at the perimeter of the carousel gear. The switches are placed on the front panel of the housing for convenient accessibly by the user.

Figure 6.5: Transparent Housing Figure 6.6: Inside Housing, Front View

Figure 6.4: Jar Carousel Assembly Drawing


The movement of the top cone piece is illustrated with the following screenshots.

The cone top piece moves up and down on the support rods to fit any height of jar up to 8 inches. The rotation of the cone top about the capped support rod allows the piece to rest on the support rods while loading and unloading a jar. This satisfies one handed usability.

Dimensioned Drawings

Detailed working drawings illustrating primary dimensions of the assembly and unique components can be found in Appendix C on pages 33-35.

6.5 Fabrication Process Production Time and Cost

The mass produced Jar Carousel would take approximately 3 minutes and 55 seconds to assemble. Each unit would cost roughly $0.94 to assemble. These estimates were determined using the Boothroyd & Dewhurst DFA rules and coding system. The results for each operation can be found in Table 6.1 on the next page.

Figure 6.7: Cone Vertical Displacement Figure 6.8: Cone Top Rotation


Table 6.1: Boothroyd & Dewhurst Assembly Analysis

0 1 2 3 4 5 6 7 8

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Housing Base 1 1 30 1.95 00 1.5 3.45 1.4

Housing Side Walls 2 1 30 1.95 00 1.5 3.45 1.4

18V Battery 3 1 30 1.95 30 2 3.95 1.6 Turntable 4 1 10 1.5 38 6 7.5 3.0 Carousel Gear 5 1 00 1.13 38 6 7.13 2.9 Top Drive Gear 6 1 01 1.43 32 5 6.43 2.6 Drive Shaft Sleeve 7 1 01 1.43 40 4.5 5.93 2.4 Drive Shaft 8 1 10 1.5 00 1.5 3 1.2 Custom Mold Top Cone 9 1 30 1.95 00 1.5 3.45 1.4 Support Rod 10 1 15 2.25 00 1.5 3.75 1.5 Capped Support Rod 11 1 10 1.5 00 1.5 3 1.2 Jameco 18V DC Motor 12 1 35 2.73 30 2 4.73 1.9 Small Spur Gear 13 1 25 2.57 30 2 4.57 1.8 Screw 8-32-3/4 in 14 11 10 1.5 38 6 82.5 33.0 Aluminum Clamp Wall 15 4 30 1.95 00 1.5 13.8 5.5 Clamp Pin 16 4 10 1.5 30 2 14 5.6 Washer 17 4 23 2.36 00 1.5 15.44 6.18 Pin Cap 18 4 10 1.5 38 6 30 12.0 Switch 19 2 30 1.95 41 7.5 18.9 7.6

TM CM

234.98 94.02

Note: These estimates would change significantly if an alternative assembly process was used (i.e. robots) which could potentially further reduce costs.

Production Methods

This design would be assembled using a top down method, as all of the parts would attach into the base and side housings. The inner components (motors and gearing) would fasten directly to the base housing. Once secured, the side housing would then be screwed into the base, concealing the inside mechanisms. The use of molded plastic parts enabled the design to be serviced and assembled easily and without complicated hardware. The design also uses one set of standard hardware, further simplifying the assembly and serviceability of the product.


Component Company/Specs Part # Unit Cost QTY Total Cost

Housing Base Injection Molded - $1.19 1 $1.19

Housing Side Walls Injection Molded - $1.39 1 $1.39

18V Battery Ace Trading 18V Replacement Battery - $1.65 1 $1.65

Turntable McMaster-Carr 1797K21 $3.15 1 $3.15

Carousel Gear Injection Mold Delrin Plastic - $2.75 1 $2.75

Top Drive Gear Boston 20 Pitch Spur - $0.25 1 $0.25

Drive Shaft Sleeve McMaster-Carr 6389K115 $0.15 1 $0.15

Drive Shaft McMaster-Carr 1263K194 $0.95 1 $0.95

Custom Mold Top Cone Injected Molded - $1.65 1 $1.65

Support Rod McMaster-Carr 8" 8587K45 $1.05 2 $2.10

Capped Support Rod McMaster-Carr 9" 8587K45 $1.19 1 $1.19

DC Motor Jameco 18V - $0.99 2 $1.98

Small Spur Gear Injection Mold Delrin Plastic - $0.39 1 $0.39

8-32-3/4 McMaster-Carr 90128A197 $0.08 11 $0.88

ABS Clamp Wall Injection Molded - $0.35 4 $1.40

Clamp Pin Injection Molded - $0.03 4 $0.12

Washer McMaster-Carr 96371A201 $0.45 4 $1.80

Switch Radio Shack 275-711 $1.19 2 $2.38

Total: $25.37

6.6 Bill of Materials

A complete Bill of Materials was created to estimate the unit cost of the Jar Carousel. A list of components, specifications, and costs can be found below in Table 6.2.

Table 6.2: Bill of Materials

An injection molding cost estimator was used to complete the BOM [7].

Based on this analysis, the unit cost of the product is $25.37. The Bill of Materials assumes pricing for a volume of 100K units. Due to economies of scale principles, producing 100,000 units significantly drops the costs of individual components. Assuming a 60% price reduction for purchased items and a 65% price reduction for machined parts, the Jar Carousel can be mass produced for a very reasonable $25.37.


6.7 Economic Analysis

In order for the Jar Carousel to be a viable market product, it must be economically feasible to mass produce it. According to market estimates, the product will have an annual sales volume of 100,000 units per year over a 4 year lifetime. A Net Present Value (NPV) analysis was conducted over the lifetime based on the following input values: Development Cost Ramp-up Cost Marketing and Support Costs Production Cost Sales Revenue

If the Net Present Value is deemed to be positive, then the product investment will yield

higher returns than if the money were simply invested at the current interest rate of 10%. If the value turns out to be negative, then the risk associated with the product will not be tolerable, since investing at the current interest rate would yield higher returns.

The NPV is calculated by this equation:

Equ. 1 [4]

Production costs were either estimated (such as development and marketing costs) or calculated (material and manufacturing costs). A detailed summary of these costs can be seen on the next page in Table 6.3.

Using the previously stated assumptions (annual sales volume of 100,000 units for 4

years, with an interest rate of 10%), the predicted net present value is $1,342,900. The

development costs for the first four quarters of the first year are approximated to be $200,000

whereas the ramp-up costs are predicted to be $100,000 from the last quarter of the first year to

the first quarter of the second year. Starting from the second quarter of the second year, the

product will be mass produced, with 25,000 units every quarter. During the four years, the

marketing and support costs are estimated to be $100,000. Labor per unit cost and material cost

are approximately $0.94 and $25.37 respectively. Therefore, the total unit production cost will

be $26.31.

The unit price for the Jar Carousel is set at $50, which is slightly less than double the

production cost per unit. Assuming every product is sold, the sales revenue will be $1.25 million

per quarter, totaling $13.75 million over the product’s lifetime. After subtracting all of the

development, ramp-up, and production fees, the company will receive over $1.3 million in

profit.


Year 1 Year 2 Year 3 Year 4

$ (in thousands of dollars) Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Development costs -200 -200 -200 -200

Ramp-up costs -100 -100

Marketing & Support Costs -100 -100 -100 -100 -100 -100 -100 -100 -100 -100 -100

Production Costs 0 0 0 0 0 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75 -657.75

Production Volume 25000 25000 25000 25000 25000 25000 25000 25000 25000 25000 25000

Unit Production Cost -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263 -0.0263

Sales Revenue 0 0 0 0 0 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250 1250

Sales Volume 25000 25000 25000 25000 25000 25000 25000 25000 25000 25000 25000

Unit Price 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05

Period Cash Flow -200 -200 -200 -300 -100 492.25 492.25 492.25 492.25 492.25 492.25 492.25 492.25 492.25 492.25 492.25

PV Year 1, r=10% -200 -181.82 -165.29 -225.39 -68.301 305.649 277.862 252.602 229.638 208.762 189.784 172.531 156.846 142.587 129.625 117.841

Project NPV 1342.9

Table 6.3: Net Present Value

Project Net Present Value = $1,342,900

6.8 Performance Calculations

Performance calculations were carried out to analyze three processes implemented in the Jar Carousel. These processes are discussed in the following categories:

1) Carousel Torque and Angular Speed

The carousel torque and angular speed section showed how the electric motor delivers a recommended 40 in-lb of torque to the rotating carousel gear. This was done via a two-stage gear reduction. Calculations derived the electric motor specifications needed for such a gear design. See Appendix D for complete calculations.

It was concluded that a 1600 RPM electric motor could deliver 40in-lb of torque to the carousel gear while having it rotate safely at 10 RPM.

2) Diamond Clamp Linear Translation

The diamond clamp assembly transforms rotation from an electric motor to linear displacement of a drive pin. The two speeds are related by a one stage gear reduction, then to a threaded rod which acts similar to a worm. See Appendix D for complete calculations.

To receive a desired 1 inch per 2 seconds translational speed of the drive pin, a motor rotating at 1440 RPM is needed.


3) Cone Top Piece Downward Force

In order for the torque of the carousel gear to be transferred to the lid of the jar, a strong frictional force must be present between the jar lid and the rubber lining of the cone. This frictional force is proportional to the coefficient of friction between the rubber and lid material, as well as the contact force between the cone and lid. This contact force is then related to the downward force that the user exerts on the cone top piece. These calculations showed how much downward force is necessary by the user to successfully transfer the torque to the jar lid. See Appendix D for complete calculations.

A user only needs to exert a downward force of 11.8 lbs to successfully add enough frictional pressure between the cone and lid to prevent slippage from occurring.

6.9 Testing Procedure

From the established design requirements, the Jar Carousel needs to be able to produce an adequate gripping force as well as 40 in-lbs of torque to open and close jars. This closing force is produced by a worm gear and spur gear combination made in two stages. In the first stage, the DC motor drives a worm gear with a specified speed and torque. These values are modified to eventually produce at least 40 in-lbs of torque and a slow enough operating speed to ensure safety and usability.

Testing the drive gears:

The gearing, as noted in the calculations section, is driven firstly by a worm to spur combination. For every rotation of the motor, the spur gear moves one tooth, creating a large gear reduction (torque increased and speed decreased). To test how well this motion is reproduced under loading, it is proposed to use a dynamometer to measure speed readings at certain torques. This experiment would be performed to rate the speed and power of the system at certain loads. Ideally the motor would move at a slower speed while under load, and then the speed would either stall at the appropriate tightness while closing or speed up when the lid was removed. This would allow the user to know when the jar was opened or closed without needing to manipulate the machine.

Testing the clamping system:

The second portion of the jar opener ideally would move quickly to either open or close the clamping system while not crushing the jar. This system would have to be tested by clamping various materials and jar sizes to ensure that the jaw force was strong enough to hold the jar and not too strong where it would crush or break the jar. A testing procedure for this section would require using different spur-spur ratios to manipulate the speed/strength ratio as well as varying the pitch of the threaded rod. In the end, analyzing this experiment would be more observational than analytical. The speed of the jaws would


have to be visually appealing, to show that the system has strength and power, but is still suitable for a household appliance.

Frictional Analysis:

In the calculations that were produced for this analysis, an approximated friction coefficient of 0.8 was used. In actuality, the coefficient would vary with different material lids. Some lids are metal, other are plastic, etc. The contour of the lids would also affect the contact patch between the lid and cone. A full contact along the circumference of the lid may not always be achieved. The Jar Carousel would need to be operated using actual jars for these approximations to be validated.

Aesthetic Testing:

All motors and gears produce noise while engaged. For the jar opener to be an accepted household product, it would have to remain very quiet. The expected levels would have to be investigated using lead user surveys, but it can be estimated that the noise levels would have to be comparable to automatic can openers. The system would need to be tested with different gear materials and gear types (spur vs. helical) to see which system produced the lowest noise. During the alpha prototype fabrication, a large amount of noise was produced in the gearbox for the clamping system. Because of the high speed and low torque of the motor, many gears were required to get the correct speed and power. This led to much more noise than anticipated. Testing for this section would most likely need to reduce the number of gears, which would reduce the volume levels. Similarly, implementing helical gears instead of spur gears in the design should also reduce noise levels.

7. ALPHA PROTOTYPE

In order to test the feasibility of the detailed design features, an alpha prototype was constructed. This prototype utilized stock materials that were easy to work with. The bulk of the housing and cone supports were made from plywood as opposed to plastic from injection molds. Tiny plastic gears, in combination with self-machined wood gears, replaced the proposed Delrin gears. Also, standard hardware was implemented for simplicity.

As previously stated, the carousel gear and drive gear were fabricated from 0.75” plywood because of their demanding sizes. A layout sketch was created using the gear feature in SolidWorks, which was then printed on multiple sheets of paper to allow a 1:1 scale. The pages were aligned, taped, and attached to the top of the plywood. Using a band saw, each individual tooth was precisely cut using the layout sketch as a guide. For the carousel gear, 120 teeth were carved into the plywood. The drive gear contained 20 teeth.


Although this was a very time consuming process, the fabrication method worked well since the gears meshed appropriately.

A huge obstacle encountered during construction of the alpha prototype was the use of plastic worm gears. Due to the rotating speeds and meshing with spur gears, the worm gears were not durable enough for sustained operation. Often times the worm would stall by fusing with its corresponding spur gear. It was also noticed that the spur was chewing away material from the worm, causing a tapered shape. The damaged worm gears can be seen below in Figures 7.3 and 7.4.

Figure 7.1: Carousel and Drive Gear Mesh

Figure 7.2: Close up of Wood Gears

Figure 7.3: Tapered Worm Defect Figure 7.4: Chewed Up Worm

Figure 7.5: Undamaged Worm


Below are pictures of the alpha prototype in its completed state. Additional pictures can be found in Appendix E on pages 41-42.

Figure 7.6: Alpha Prototype Figure 7.7: Cone Top Piece Down

Figure 7.8: Threaded Rod Assembly


Although materials differed from the professional specifications, the alpha prototype did a successful job in pointing out design flaws, illustrating functionality, and offering insight for future improvements.

8. BETA PROTOTYPE

Construction of the beta prototype incorporated changes from the alpha prototype to allow better performance and durability.

The primary difference between both stages was the removal of the worm gears. As mentioned before, the worm gears were not suitable for sustained operation conditions. To combat this issue, the drill chuck and motor was instead connected directly to the drive gear shaft. This increased the rotational speed of the carousel gear in the process, yet provided considerably more robustness. Because the chuck had to be positioned in a vertical orientation, it was moved outside of the housing. A simple plywood holder and dowel rod assembly held the chuck in place. See Figure 8.1 on the following page.

Figure 7.10: Diamond Clamp Top View

Figure 7.9: Chuck and Worm


The other modification found on the beta prototype was the installation of both switches. The wires was soldered inside the housing and connected to the switch prongs. As seen in Figure 8.2, one switch controlled the diamond clamp, while the other controlled the carousel gear. The wiring was done in such a way that the motor changed spin directions with the different switch positions.

Additional beta prototype pictures can be seen in Appendix E on page 42.

Figure 8.1: Chuck Holder

Figure 8.2: Electric Switches


Construction Costs

To build the alpha and beta prototypes, many materials needed to be purchased. These included plywood for the housing and gears, aluminum for the diamond clamp, switches, and miscellaneous hardware. The base for the diamond clamp was cut using a water jet from the learning factory.

The total costs of building both the alpha and beta prototypes was about $150. The MNE Department paid for the turntable and water jet expenses. The aluminum used for the diamond clamp and diamond base was purchased; however, stock aluminum from the Learning Factory could have been used instead free of charge.

A construction Bill of Materials can be found in Appendix E on page 43.

9. TEST RESULTS AND DISCUSSION

Beta Testing

After completing the beta prototype, its performance was tested by attempting to open and close jars of various sizes and materials. Two jars (one plastic and one glass) were successfully opened and closed upon completion of testing. Many design calculations were confirmed as a result while other issues came to light for the first time. In accordance with the performance calculations, the carousel gear supplied sufficient torque to the lid of the jar. The diamond clamp system also applied adequate pressure to the jar bottoms. However, slight jar slippage was noticeable at this contact point. The slippage did not cause opening failures, but hindered the timeliness of the process. The largest issue that arose during testing was the lack of contact force exerted on the jar lids by the cone top support. It was calculated that roughly 12 lbs of downward force was needed from the cone to produce enough torque through static frictional forces. Originally, this downward force was intended to come from the user’s hand, yet due to the location of the power switches, the current design was not compatible for one-handed operation. Two hands were needed to engage the motors and simultaneously keep constant pressure on the jar lids. Overall, the testing matched well with expectations dictated from performance calculations. The redesign of the gearing minimized mesh complications and both motors supplied enough power to move the assemblies.


Future Improvements

To improve the design for one-handed operation, two intuitive solutions seem prevalent. First, the switches can be moved to the top cone support so that the user can both supply power and press down on the support. This, however, creates a safety concern since the top is spinning and the user is vulnerable for injury. A better solution would be to redesign the top support to have it apply 12 lbs of force without needing a user to do so. This could be done by adding weight, utilizing springs, or enabling a vice-like system. Finally, selecting a rubber lining with a higher coefficient of friction against plastic and glass should rectify any slippage issues.

Project Takeaways

This jar opener project was extremely helpful to upcoming engineers in so many ways. It taught essential lessons in time management, teamwork, design, fabrication, and testing procedures. A primary lesson learned by Team I was that nothing works the first time. No matter how many flaws and complications are anticipated beforehand, more issues certainly came about down the road. It was important to remain focused and systematic throughout the entire process so these unpredicted troubles could be dealt with in a smooth, professional manner.

The team also learned through hands-on experience that machining is enormously time consuming. Wood working and especially metal working took patience. Especially with a crowded shop environment, it was imperative to commit more time than anticipated to any construction process.

Finally, the team gained much needed experience in formulating design reports. This was the first course that a Proposal, Design Report, and Final Report were required. These items are certainly fundamental in industry. Engineering is only as good as the documentation of ideas. Quality technical writing cannot be emphasized enough, and the team undoubtedly became better writers throughout the semester.

Although the Jar Carousel project required tremendous efforts from the team, it was an enjoyable product to develop and exceedingly educational throughout the process.

10. CONCLUSION AND RECOMMENDATIONS

Senior citizens, people who suffer from arthritis, and amputees are in need of a solution to resolve their simple daily problem from the lack of energy for opening jars. Such a trivial task may seem easy for a healthy person, but could be very frustrating for


those who are not as lucky. The invention of an automatic jar opener that could open and close jars by one switch could help solve this problem for so many.

For this good cause, the team has come up with the final concept for the jar opener, called the Jar Carousel. This product will satisfy the customer needs and deliver an effective, elegant product. Through prototype testing procedures, performance calculations were verified and improvements are ready to be instilled into the design. The product’s durability, functionality, and price will compete with current products on the market. The Jar Carousel, if sold for a reasonable $50, is predicted to make a profit of $1.3 million over its anticipated 4 year lifetime. It will certainly serve as a great investment while also helping out the ones who need the most care by making their lives a little easier, which is the universal goal of all invention.

11. REFERENCES

[1] "CDC - Arthritis - Data and Statistics - Arthritis Related Statistics." Centers for Disease Control and Prevention. 20 Oct. 2010. Web. 24 Feb. 2011. <http://www.cdc.gov/arthritis/data_statistics/arthritis_related_stats.htm>.

[2] "Amazon.com: One Touch Jar Opener: Kitchen & Dining." Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & More. Web. 24 Feb. 2011. <http://www.amazon.com/onetouch-jaropener-One-Touch-Opener/dp/B001E23RLM/ref=sr_1_3?ie=UTF8&qid=1298591804&sr=8-3>.

[3] "Amazon.com: Black & Decker Lids-Off Jar Opener: Kitchen & Dining." Amazon.com:

Online Shopping for Electronics, Apparel, Computers, Books, DVDs & More. Web. 24 Feb. 2011. <http://www.amazon.com/Black-26-Decker-Lids-2dOff-Opener/dp/B0012LG2HQ/ref=cm_cr_pr_product_top>.

[4] Ulrich, Karl T., and Steven D. Eppinger. Product Design and Development. 4th ed. Boston ; Montre%u0301al: McGraw-Hill Higher Education, 2008. Print.

[5] "Plastic Properties of Acrylonitrile Butadiene Styrene (ABS) ." Dynalab Corp. N.p., n.d.

Web. 9 Apr. 2011. <http://www.dynalabcorp.com/technical_info_abs.asp>. [6] "DuPont Delrin acetal resin." DuPont. N.p., n.d. Web. 9 Apr. 2011.

<http://www2.dupont.com/Plastics/en_US/Products/Delrin/Delrin.html>. [7] Kazmer, David O. "Java Injection Molding Cost Estimator." University of Massachusetts

Lowell. N.p., n.d. Web. 13 Apr. 2011. <http://kazmer.uml.edu/Software/JavaCost/index.htm>.


APPENDIX A – PROJECT MANAGEMENT

Team Roles

Dan Aglione – Executive Summary, Introduction, Material/Component Selection, Detailed Models and Drawings , Results and Discussion

Matt Steindorf – Concept Generation, Concept Selection, Chief Prototype Fabricator, Bil l of Materials, Testing Procedure, Scheduling

Qi Zhang – Customer Needs Assessment, Economic Analysis, Performance Calculations, Conclusion, References

Figure 2.1: Project Schedule Gantt Chart


APPENDIX B –CUSTOMER DATA

Table 2.1: Translated Customer Needs

Prompt CUSTOMER REVIEW INTERPRETED NEED SPECIFICATIONS

Likes - Black and Decker

IT IS A GOOD KITCHEN

DECORATION. THE JAR OPENER NEEDS TO BE

AESTHETIC. ROUNDED EDGES

INJECTION MOLD

MATERIALS

CLEAN

APPEARANCE/

COLOR SCHEME

IT IS EASY TO USE AND

STURDY. THE JAR OPENER NEEDS TO BE

ERGONOMIC. EASY TO MAINTAIN

CLEAR USAGE

LABELS

Likes - One Touch

IT FITS ALMOST ANY JAR

SIZE AND IT NOT HARD

FOR STORAGE.

THE JAR OPENER NEEDS TO SMALL

FOR STORAGE. COMPACTIBLE

IT IS EASY TO USE AND

INEXPENSIVE. THE JAR OPENER NEEDS TO BE

AFFORDABLE. CHEAP MATERIALS

SMALL PART

COUNT

Dislike - Black and Decker

IT DOES NOT FIT ALL SIZE

JARS. THE JAR OPENER NEEDS TO FIT

VARIETY OF JAR SIZES. ADJUSTABLE

MECHANISM

IT DOES NOT FIT ALL SIZE

LIDS. THE JAR OPENER NEEDS TO FIT

VARIETY OF JAR HEIGHTS. ADJUSTABLE

MECHANISM

Dislikes - One Touch

IT IS SLOW AND IT BREAKS

AFTER A FEW USAGES. THE JAR OPENER SHOULD OPEN

JARS FASTER THAN BY HAND. HIGH POWER

MOTORS EFFICIENT

GEARING

IT TAKES UP TOO MUCH

POWER. THE JAR OPENER SHOULD REQUIRE

LESS POWER. EFFICIENT MOTOR EFFICIENT BATTERY

THE BUTTON ON THE JAR

OPENER WAS TOO BIG

THAT I ACCIDENTLY PRESS

IT.

THE JAR OPENER SHOULD HAVE AN

ON AND OFF SWITCH. PROVIDE ESSENTIAL

USER CONTROLS

ILLUMINATED

PUSH

BUTTON/TOGGLE

SWITCHES

BUTTONS

CLEARLY

SHIELDED FROM

ACCIDENTAL USE

THE JAR OPENER

STARTLED ME WHEN IT

OPENED THE JAR SMOOTH OPENING ACTION

SAFE MOTOR

CONTROL SMOOTH DRIVE SHIELDED USER

Suggested improvements

IT NEEDS TO HAVE A

LONGER LIFE SPAM. THE JAR OPENER MUST BE STURDY.

ROBUST MATERIALS

SELECTION

ADEQUATE

HARDWARE

SELECTION

IT NEEDS TO FIT ALL

DIMENSIONS OF ANY

JARS.

THE JAR OPENER MUST FIT A

VARIETY OF JARS.

Team I Proposal 31 | P a g e 4/29/2011

APPENDIX C – CAD MODEL AND DETAILED DRAWINGS

Figure 6.9: Assembly Front View

Figure 6.10: Diamond Clamp

Figure 6.11: Worm and Spur Contact Figure 6.12: Threaded Rod Assembly


Figure 6.13: Transparent Right View Figure 6.14: Cone Cutout in Top Piece

Figure 6:15: Assembly Exploded View Figure 6.16: Housing Exploded View


Figure 6.17: Base Housing Drawing

Figure 6.18: Outer Clamp Drawing


Figure 6.20: Carousel Gear Drawing

Figure 6.19: Inner Clamp Drawing


Figure 6.21: Threaded Rod Motion Drawing

Figure 6.22: Cone Top Piece Drawing


APPENDIX D – CALCULATIONS

Information unknown:

rotational speed for motor 1 (RPM)

rotational speed of motor 2 (RPM)

Information known:

Table 6.4: Gearing Specs

Gears Characteristics of Gear Number of Teeth

Radius (in)

Worm Gear that is connected to motor 1 (pitch = 20) - -

Gear 1 The biggest gear that rotates the top cone (carousel gear) 120 6.0

Gear 2 The gear that drives the Gear 1 (drive gear) 15 0.75

Gear 3 The smaller gear that is at bottom of shaft connecting to Gear 2 and is driven by worm that connects to motor1

20 0.50

Gear 4 Gear that drives the rod controlling diamond clamp 20 0.50

Gear 5 Smaller gear that is connected to Gear 4 and motor2 10 0.25

Stipulations:

(Desired Carousel Torque)

(Desired Rotational Speed)

(Desired Translational Speed)

Interpretations & Techniques:

The Gear 1 that connects to the top should rotate 10 times per minute.

Since worm is connected to Gear 3, which is connected to Gear 2, rotational speed for Gear 2

needs to be calculated first before rotational for Gear 3.

When worm rotates 20 times, Gear 3 rotates once.

It takes 24 revolutions of thread to make diamond move 1 in. Therefore, the rotational

speed needs to be 12RPM for Gear 4.


Since Gear 4 is connected to Gear 5, the rotational speed of Gear 5 can be found. Gear 5 is

connected directly to motor2; therefore, the speed of motor2 is the same as the angular

speed of Gear 5.

Torque of motor 2 is not a significant factor.

Relevant Equations:

1 rev/min * (2 pi radian / 1 revolution) * (1 min/60s) = rad/sec

1) Carousel Torque and Angular Speed

Gear Reduction Stage 1 Ratio

Gear 1: Gear 2


Gear 3: Gear 2

(same shaft)


1: 1


Gear 3: Worm

1: 20

Rotational Speed Gear 2


Rotational Speed Worm Gear

= 20 * (80RPM)

Motor 1 speed = 1600 RPM

2) Diamond Clamp Linear Translation

Rotational Speed of Threaded Rod

24 rev (rod) = 1in translation (diamond)


Gear Reduction Ratio

Gear 4: Gear 5


Motor 2 speed = 1440 RPM

3) Cone Top Piece Downward Force

Assumptions: Maximum torque of 40 in-lb is needed to open a lid. Minimum lid diameter is 2 inches. Coefficient of friction between rubber and lid is approximately 0.8. Cone top piece weights 2 lbs. The first calculation shows how much frictional force is needed to exert 40 in-lb of torque on a 2 in diameter lid.

This represents the frictional force needed to effectively grip the lid. Next, the contact force can be determined.


This contact force is related to the downward force of the cone piece. This force is comprised of both the weight of the cone piece, and also the pushing force from the user. From the cone geometry, the angle of the cone relative to the horizontal is approximately 49o.

Now since the cone grips the jar lid along its entire circumference, the downward force acts as a distributed load. The length of the force is simply the lid’s circumference length.

This is a reasonable amount of force to expect from the user and will effectively transfer enough

frictional force to the lid from the rubber insert.


APPENDIX E –PROTOTYPE FABRICATION

Alpha Prototype

Figure 7.14: Cone Rubber Lining Figure 7.13: Diamond Clamps

Figure 7.12: Wood Housing

Figure 1: Inside Mechanisms


Beta Prototype

Figure 7.16: Water Jet Clamp Guides

Figure 8.3: Beta Prototype Figure 8.4: Inside of Beta Housing

Figure 7.15: Electric Switches


Material Description Unit Cost Quantity Total Cost

Plywood Plytanium 23/32 x 4 x 8 Sturd-I-Floor T&G Plywood $22.97 1 $22.97

Dowel Rod Madison Mill 1"Dia. x 36"L Oak Round Dowel $3.98 2 $7.96

Hardware Grip-Rite 218-Pack 1-1/4" Steel Bugle Head Wood Screw $7.89 1 $7.89

Baseplate Multipurpose Aluminum (alloy 6061), 1/4" Thick X 10" Width X 1' Length $15.97 1 $15.97

Clamp Material Steelworks Aluminum Flat 1/8 x 2 x 8' $22.42 1 $22.42

Hinges Gatehouse 3-1/2" Butt/Mortise Hinge $2.58 1 $2.58

Water Jet Learning Factory machine costs $10.47 1 $10.47

Turntable McMaster- Carr #18635A52 $31.59 1 $31.59

Small Motor MOTOR,DC,6-18V,9820RPM,0.7A $2.95 1 $2.95

Cone Plews Plastic Funnel $0.96 1 $0.96

Threaded Rod The Hillman Group Flange Bolt 8-32 x 4" $2.41 1 $2.41

Clamp Lining Chef Craft Solicone Pot Holder $4.59 1 $4.59

Cone Lining Progressive Flexible Jar Grip $1.12 1 $1.12

Pipe Straps AMERICAN VALVE 3/4" Galvanized 2-Hole Pipe Strap Ceiling Support $2.07 4 $8.28

Electric Switches RadioShack Black Flip Switch SPDT $2.99 2 $5.98

Zip Ties Gardner Bender 8" long $0.10 3 $0.30

Finish Nails The Hillman Group Finish Nails 6D $1.24 1 $1.24

Total: $149.68

Table 7.2: Construction Bill of Materials


APPENDIX F – CONCEPT SKETCHES

Figure 3.2: Scissor Bottom/Tires Top

This concept uses a system of tires to drive the lid off of the jar using friction. There is a clamping system at the bottom which scissors shut around the diameter of the jar. This system would be constructed out of aluminum and would have to contain steel springs to provide tension on the lid from the tires. While this system could quickly remove the lids, operation would be difficult for the consumer without the use of two hands. The tires would have to be adjusted individually in order for the jar lid to fit properly. A disadvantage of this system is that there are two independent control systems, and the user would have to operate them in sequence.


Figure 3.3: Strap Bottom/ Cone Top

This concept invokes a rubber strap to secure the bottom of the jar while a cone is used to apply torque to the lid. Both components operate one at a time, incorporating a toggle switch to link the motor to the appropriate device.

The jar is first rested upon a stationary base plate. Concentric guiding circles are printed on the base to assist in centering the jar. A curved support is then slid along the base plate to make contact with the jar. The rubber strap is fed through this support and wound around a rotating rod. With the touch of a button, the rod is spun in one direction, reducing the length of the strap in the process. This tightens its contact with the jar. When the rotation direction of the rod is reversed, the strap loosens its grip and the jar can be removed with ease.

The top support is an aluminum bar that has a cone-shaped cutout in the center. This cutout is coated with a rubber-like material with a high coefficient of friction. Holding up the top bar are two support cylinders, each fastened to an outer ring on the base plate. This outer ring is spun via a center axis rotation which is incorporated into a gear box housed in the base plate. Once the jar is properly secured, a button initiates the gears, consequently rotating the outer ring. The sheer weight of the cone assembly provides enough contact pressure to the lid, unscrewing it from the jar threads. Again, when the gear rotations are reversed, the cone turns the lid back onto the jar.


Figure 3.4: Scissor Bottom/Straight Clamp Top

Straight clamp top and scissor bottom is a design that the top of the jar opener has a straight clamp that could move up and down depending on the height of jars, and the size of the clamp could be changed when the jar opener is power on. It would be powered by the motor, and once it reaches a certain torque, the motor will continue to spin without decrease in size.

The scissor bottom idea was generated from the wedge jar opener design; however, man power needs to be eliminated in this design. The scissor bottom is there to hold the jar tight; it is a scissor design along with a bracket that prevents jar from moving around. It gives three points of contacts on the jar which would lock the jar tight. The size of this prototype would restrain the size of jars that the opener can open, which could be a challenge.


Figure 3.5: Scissors Bottom/ Handcuffs Top

Handcuffs top and scissor bottom is a design that has a handcuffs-like design top that looks like two U shaped pieces of metal that are flipped to form a circle in the middle. There are teeth on each pieces and it is attached onto a shaft. When the shaft turns, the pieces could tighten or loosen the circle, which is used to grab onto the lid of the jar. The handcuffs top design could also move up and down depending on the height of jars, and the size of the clamp could be changed when the jar opener is power on. It would be powered by the motor, and once it reaches a certain torque, the motor will continue to spin without decrease in size.

The scissor bottom idea was generated from the wedge jar opener design; however, man power needs to be eliminated in this design. The scissor bottom is there to hold the jar tight; it is a scissor design along with a bracket that prevents jar from moving around. It gives three points of contacts on the jar which would lock the jar tight.

The potential problem with this design would be very similar to the benchmark product, Black and Decker Lid Off Opener, because the size of the U shape metal would determine the maximum diameter of the possible jars that would be opened.


Figure 3.6: Adjustable Diamond Bottom/ Cone Top

This concept follows the same opening principle as the strap/cone permutation, yet investigates a different bottom mechanism. Instead of using a rubber strap to tighten the jar in position, two adjustable wedges secure jar bases of various sizes. Each wedge has a pin at its vertex, in addition to two pins that fix both wedges together end to end. This creates a parallelogram of varying angles so any sized jar can be squeezed in the middle. Another benefit of this diamond design is that no matter the size of the jar, it always be centered on the base plate. This ensures that the cone top interfaces the lid properly. The mechanism is adjusted by having one pin connected to a rack and pinion. When the pinion spins one direction, the pin moves inward, enlarging the center area. Having the pinion rotate in the opposite direction pulls the pin outward, thus closing the inside area.


Figure 3.7: Belt Driven Top/ Strap Bottom

This system would operate by strapping the jar into a metal enclosure and locking it in place with a worm screw powered by the electric motor. Once the jar is locked in place, the operator would lay a belt around the lid. This belt would be connected to a drive shaft which would be powered to open or close the jar. There are several advantages to having a belt driven system, one being that you have a very high surface area connection with the lid, making it potentially easier to open a stuck on lid. The strap also has a couple of advantages one being that it is very strong and can conform to different sized jars easily. The belt would have to be adjusted for different sized jars, and this is the main disadvantage. Adjusting a belt using idler gears and motors would vastly increase the complexity of the design.

Date post:	02-Jul-2015
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Final Report - Team I

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